Filtering Activity and Nutrient Release by the Keratose Sponge Sarcotragus spinosulus Schmidt, 1862 (Porifera, Demospongiae) at the Laboratory Scale

Roberta Trani,Giuseppe Corriero,Maria Concetta De Pinto,Cataldo Pierri,Maria Scrascia,Caterina Longo,Carlo Pazzani,Maria Mercurio

doi:10.3390/jmse9020178

Abstract

Sponges are an important constituent of filter-feeder benthic communities, characterized by high ecological plasticity and abundance. Free bacteria constitute an important quota of their diet, making them excellent candidates in aquaculture microbial bioremediation, where bacteria can be a serious problem. Although there are studies on this topic, certain promising species are still under investigation. Here we report applied microbiological research on the filtering activity of Sarcotragus spinosulus on two different concentrations of the pathogenic bacterium Vibrio parahaemolyticus in a laboratory experiment. To evaluate the effects of the filtration on the surrounding nutrient load, the release of ammonium, nitrate, and phosphate was also measured. The results obtained showed the efficient filtration capability of S. spinosulus as able to reduce the Vibrio load with a maximum retention efficiency of 99.72% and 99.35% at higher and lower Vibrio concentrations, respectively, and remarkable values of clearance rates (average maximum value 45.0 ± 4.1 mL h−1 g DW−1) at the highest Vibrio concentration tested. The nutrient release measured showed low values for each considered nutrient category at less than 1 mg L−1 for ammonium and phosphate and less than 5 mg L−1 for nitrate. The filtering activity and nutrient release by S. spinosulus suggest that this species represents a promising candidate in microbial bioremediation, showing an efficient capability in removing V. parahaemolyticus from seawater with a contribution to the nutrient load.

Highlights

Marine sponges (Phylum Porifera) are ancient metazoans that dominate many of the hard-bottom benthic habitats around the world along a wide geographical distribution and depth range [1,2]
The importance of free bacteria in the diet of sponges [16] and the ability to concentrate and digest large numbers of microorganisms suggested that sponges could be effective in reducing bacterial abundance, including microbial pollution, caused by sewage in coastal areas [17], such as near mariculture facilities where bacteria, including potentially pathogenic species, are often abundant [18,19,20,21,22,23,24,25,26,27,28,29,30]
The filtering activity and nutrient release by spinosulus obtained in the present

Summary

Introduction

Marine sponges (Phylum Porifera) are ancient metazoans that dominate many of the hard-bottom benthic habitats around the world along a wide geographical distribution and depth range [1,2]. In highly anthropized marine environments, such as intensive or confined mariculture systems, the excessive release of excreta from farmed species and organic matter from uneaten feed create favorable conditions for pathogenic bacteria growth, especially Vibrio, responsible for diseases and high mortality in target species, with consequent economic losses [31,32,33,34,35,36,37]. To overcome this problem, the use of antibiotics has spread despite the increase in production costs and the negative consequences on farmed species and the surrounding environment. Antibiotic residues can remain in products for human consumption and antibiotics released into the environment can induce the development and spread of antibiotic-resistant bacteria in the food chain [38]

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Results

Conclusion